This invention relates to thermal transfer recording media to be used for, e.g. thermal transfer printers.
In the field of thermal transfer printers, edge head printers have been widely employed in these years.
These edge head printers have advantages of achieving a high printing speed (about 8 inch/sec) in spite of the simple structure thereof and being applicable to recording media having rough surface such as non-coated paper (so-called rough paper).
FIG. 2 shows an example of conventionally known thermal transfer recording media for these edge head printers.
In this thermal transfer recording medium 101 shown in FIG. 2, a peel layer 103 is formed on a base material 102 and a highly viscous ink layer 104 is further formed on the peel layer 103. On the other hand, a heat-resistant lubricating layer 105 is formed on the opposite face of the base material 102.
In recent years, printing speed has been more and more elevated (about 12 inch/sec). Therefore, it is impossible under the present conditions to obtain a clear image by printing on non-coated paper at a high speed.
In high-speed printing, there arises another problem that the resistance to rubbing (rub resistance) of the printed image is worsened.
The present invention, which has been completed to solve these problems encountering in the prior art, aims at providing thermal transfer recording media capable of providing a clear image in case of high-speed printing on non-coated paper and improving the rub resistance.
To achieve the object as described above, the present invention provides a thermal transfer recording medium comprising of a base material and a peel layer including a wax (A) and an ink layer including a styrene resin (B), a binder component (C) and a coloring component (D) laminated successively on the base material, wherein the wax (A) is compatible with the styrene resin (B).
The present inventor conducted studies on the transfer of a thermal transfer recording medium for non-coated paper. As a result, it has been found out that as the printing speed is elevated, no transfer occurs at the interface of the base material and the peel layer at the area to be peeled but peeling arises at the inner part of the peel layer. The peeling finally moves at the interface of the peel layer and the ink layer.
By using a peel layer including a wax (A) and an ink layer including a styrene resin (B) compatible with the wax (A), the peel layer sufficiently adheres to the ink layer even at the step of heat transfer. Thus, no peeling arises at the interface of the peel layer and the ink layer. The peel layer and the ink layer are transferred together from the base material, thereby ensuring smooth transfer of the ink layer and sufficient protection after the completion of printing.
According to the present invention, therefore, a clear image can be obtained and the rub resistance can be improved even in case of printing on non-coated paper at a high speed.
In the present invention, it is also effective to regulate the weight ratio of the styrene resin (B) to the binder component (C) to 10:90 to 50:50.
According to the present invention, the sharpness and rub resistance of a printed area can be improved.
When a binder component (C) including an ethylene-vinyl acetate copolymer is employed as in the present invention, the ink layer has a high viscosity and thus bleeding into non-coated paper can be prevented, thereby providing a clear image. In this case, moreover, a rubbery elasticity can be imparted to the ink layer and thus the rub resistance can be elevated.